EPA announced the results of its preliminary assessment of potential
health risks for workers, as well as ecological effects and environmental
risks, associated with wood preservatives containing arsenic and/or chromium.
This preliminary assessment included an evaluation of the potential risks
to handlers and post-application workers from exposure to these chemicals.
The assessment was a cooperative re-evaluation between the US EPA and
Health Canada's Pest Management Regulatory Agency (PMRA) under NAFTA.
The preliminary risk assessment is available from Regulations.gov in Docket Number EPA-HQ-OPP-2003-0250.

Which wood preservatives were included in this
preliminary assessment?
The predominant inorganic arsenical preservatives used by the wood treatment
industry are mixtures of "chromated copper arsenate," more commonly
referred to as "CCA." Other wood preservatives covered include: ammoniacal
copper arsenate (ACA), and ammoniacal copper zinc arsenate (ACZA). Acid
Copper Chromate (ACC) is also a wood preservative containing arsenic
and/or chromium; however, it is subject to a voluntary cancellation
action and is not part of this assessment. Preservatives such as ACZA
and ACA are used for specialized applications or in cases where wood
penetration by CCA chemicals cannot be achieved (e.g., ACA and ACZA
are used on large dimension wood products made from hard-to-treat wood
species such as Douglas Fir). These chemicals are referred to as "heavy
duty wood preservatives."

What were the occupational exposure scenarios included
in this preliminary risk assessment?
The occupational exposure chapter addresses potential exposures and
risks of chromium and arsenic to humans who may be exposed to CCA and
related arsenicals and chromated wood preservatives in "occupational
settings" including: (1) handlers (mixers, loaders, applicators) of
CCA and related pesticide products; and (2) individuals who are exposed
to CCA and related pesticides through postapplication activities. The
occupational settings are characterized as wood treatment plants where
wood is pressure treated. Therefore representative occupational handler
exposure scenarios were developed for treatment plant workers only.
Potential postapplication exposures also may occur in occupational settings
such as wood pressure treatment plants where treated lumber is handled
for QA/QC testing, or storage/transport, or in commercial or institutional
outdoor settings where the wood is fabricated into structures and professionally
installed. However, occupational postapplication exposure scenarios
were developed for treatment plant workers only, since it is anticipated
that handling freshly-treated wood and performing postapplication work
tasks in treatment areas constitute postapplication scenarios with the
potential for maximum exposures.

What were the findings of the preliminary risk
assessment?
Because this is a preliminary assessment, it is premature for EPA to
reach conclusions about the potential for wood preservatives containing
arsenic and/or chromium to contribute to cancer risks in workers, or
regarding environmental or ecological risks. While EPA has identified
some potential risks of concern, the risk estimates provided in this
assessment are of a preliminary nature and subject to refinement. The
process that EPA uses to review chemicals through reregistration is
intended to gather additional information and input from the public
and stakeholders about exposure and risk that will be used to revise
the risk estimates.

What recommendations does the Agency make for handlers?
The Agency is in the process of evaluating exposure and risk assessment
data for workers involved with pressure treatments using inorganic arsenicals.
General precautions for handling treated wood include always washing
hands thoroughly after contacting treated wood, especially prior to
eating and drinking, and ensuring that food does not come into direct
contact with any treated wood. Workers and consumers should follow the
recommendations in the Consumer Awareness Program, including wearing
gloves when handling wood, wearing goggles and dust-mask when sawing
and sanding, and never burning CCA-treated wood.

Were potential risks to children included in this
preliminary risk assessment?
No; these potential risks are being carefully evaluated through a separate
but similar process. Refer to the CCA fact sheet for information on that assessment, and the Scientific Advisory Panel's report.

What has been the role of Canada's Pest Management
Regulatory Agency (PMRA) in the development of this preliminary risk
assessment?
The preliminary risk assessment is a cooperative re-evaluation between
the US EPA and Health Canada's PMRA under NAFTA. Both countries have
contributed to the study review and peer review process. Exposure data
used in the preliminary risk assessment were collected from both US
and Canadian wood-treatment facilities and both countries are participating
in the public comment process. As the assessments are finalized, EPA
will continue to work closely with Canada since the goal of these efforts
is to develop science and regulatory conclusions amenable to both agencies.
More information available from the PMRA website.